Preheat oven to 400⁰F/204⁰C. Line muffin tin with 10 muffin paper or grease the muffin tin.

In a bowl, whisk together, eggs, granulated sugar, oil, orange zest( keep 1 teaspoon orange zest aside) and ½ cup orange juice, vanilla extract, and sourdough starter until incorporated.

In another bowl mix flour, baking powder and salt mix well then add this dry ingredient to wet mixture until combined.

Pour the batter into the prepared muffin tin and bake for 400⁰F/204⁰C for 8 minutes . Then reduce the temperature for 350⁰F/180⁰C for 10 minutes or until the muffin is golden in color and toothpicks comes out clean when it is inserted.

When its muffin is done, finish the muffin brush with orange juice, this will keep the muffin moist, then dust with powdered sugar if you want, I did not.